I tried to start my x30 before the pre-final saturday and nothing, no click, the starter didn’t try to turn and I noticed the battery starting to smoke at the terminal so I immediately turned the switch off and disconnected the battery. Disconnected the cable from the starter and saw about 12v with the key in the start position, saw about 4v across the starter with the cable re-connected to the starter.

Is this normal starter failure and I need to buy the brush kit, or is this something more serious that I need to dig deeper into?

Brian,
The normal failure would have been the braided wire braking off the motor brush and nothing happening. There would have been no sound, no smoke, no anything. So you’re going to have to look deeper. You didn’t if your motor was OK. Is it seized? After that, I’d first look for a Bendix that wouldn’t spin or the starter motor that wouldn’t turn. If you have a volt meter, check for resistance from the starter terminal to the case. I suppose there is a chance that the brush wire broke off and is touching the case. You’re going to have to open up the starter to find out.